Optical wavelength channel control devices, such as wavelength add-drop filters, can be made at low cost by integrating optical filters and power-dissipating active elements, such as thermooptic phase shifters, together on the same substrate. However, the thermooptic phase shifters dissipate power, whereas the optical filters need to be held at constant temperature. Since the power dissipation from the thermooptic phase shifters, the ambient temperature, and the characteristics of the ambient airflow over the device may vary with time, the temperature of the substrate tends to vary with time as well. However, the performance of the optical filters will be sacrificed if the substrate temperature cannot be maintained constant. FIG. 3 shows a prior art integrated optical device arrangement to hold constant substrate temperature, where the optical filters 101 and the thermooptic unit 102 are formed on a substrate 103 that is mounted to a thermoelectric cooler (TEC) 201 which is mounted on a heat sink 106. This prior art arrangement generally results in a thermal management solution consuming a very large amount of electrical power (on the order of that dissipated by the integrated optical device) which could otherwise be used to add more optical functionality to the device. This prior art solution also usually requires a stiff mechanical connection between the substrate 103 and the heat sink (106). This often results in unwanted strains and vibrations on the optical device due to environmental changes, often adversely affecting the optical response.
What is desired is a low-power technique to dissipate the heat from the substrate while holding the substrate at a constant temperature. Furthermore, it would be desirable for this technique to have only a flexible mechanical connection between the substrate and the heat sink.